EXPERIMENT ON MACHINABILITY OF NEW DEVELOPED LOW CARBON SULPHUR FREE-CUTTING STEEL

CHEN Ming  LIU Gang  ZHANG Xiaohui  SHEN Zhong  YANG Guijun

(School of Mechanical Engineering, Shanghai Jiaotong University, Shanghai 200240)

Abstract: Several new developed kinds of low carbon sulphur free-cutting steel are studied. Influences of major elements on the shape, size and distribution of sulphide inclusion are investigated by means of their metallographic structures. The cutting force, tool wear, surface quality, chip deformation and morphology are studied systematically, which reveals the cutting mechanism and influences of major elements on machinability of the new low carbon sulphur free-cutting steel. Experiment conclusions show that materials containing the sulphide inclusion with small length width ratio, big size, homogeneous and dense distribution have better machinability. The tool life can be prolonged by increasing the content of sulphur. The content of Al and Si which serves as deoxidizer should be controlled in a proper range. With overabundant deoxidizer the morphology of sulphide inclusion is bad, additionally, much solidness is formed which is bad for the tool life and surface quality. Experiment results have great practical significance to improve the evaluation system of material machinability and the development of new types of free cutting steel.

Key words: Free-cutting steel Sulphur Machinability Influence of elements

CLC No: TG156

国家自然科学基金资助项目(50675134). Received 20060823, received in revised form 20070523